When hard fun maybe isn't so much

I have been playing my potty game Sudoku for about five weeks now.  I find it a wonderful waste of time. . . well not really a waste I suppose as you'll see from the video I am working on.  It's teaching me a few things.  I actually LIKE working with numbers better than I did before.  Here's the thing though.  When I was playing "just for fun" I found I really enjoyed it and got no small amount of satisfaction from beating the game.  However, for this project I decided to make the video mentioned earlier.  I was trying to shoot scenes that demonstrated how I was learning the game. . . . and I noticed myself becoming frustrated . . . even agitated because I had a "deadline" with a specific accomplishment desired.  Not as much fun anymore.  I was surprised that a different motivation could make the game LESS enjoyable!